Field of the Invention
The present invention relates to a suspension unit. More specifically the invention relates to a suspension unit for use in a washing machine for dynamically supporting a washing machine tub and drum assembly.
Description of the Related Art
Conventional washing machine tub and drum assemblies are hung by springs or spring and damper assemblies which act in tension. A significant disadvantage of hung systems is that typically the suspended assembly is hung from the top of the cabinet enclosing the machine internal components. Therefore the cabinet must be structurally strong enough to carry all the oscillating suspension forces. An advantage of a hung system is that it is inherently self centering because the lowest potential energy state is in the centre of the movement range. Therefore a hung system is stable.
Using suspension units, for example suspension struts, in compression to support the tub from below enables the forces generated by the tub dynamic assembly to be transmitted directly into the base of the washing machine. The cabinet therefore has less structural demands and can be somewhat isolated from the vibration source of the drum and tub.
The main disadvantage of a suspension system that operates in compression is that it does not inherently self centralize the dynamic assembly and therefore can provide less stability than a hung system.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is an object of the present invention to provide an improved suspension unit or laundry machine, or to at least provide the public or industry with a useful choice.